Machine for measuring friction.



H. HESS. MACHINE FOR MEASURING FRICTION,

APZLIOATIOH FILED AUG. 11, 1909.

Eatentefl 3556?. 17, 1914;.

5 SEEETS-8HEET 1.

y i/bwc as c o W H. HESS.

mcams FOR. MEASURING smnon.

APPLIG TION FILED AUG 11v 1909.

'5 173815 Patented Nov. 17, 19M

5 SHEETS-SHEET 2.

aHo' 213 HESS.

MACHINE FOR MEASURING FRICTION.

APPLICATION FILED AUG.11, 1909.

Patanted Nev. 1?, 191%.

5 SEEETSSHEET 3.

H. HESS.

MACHINE FOR MEASURING FRICTION.

APPLIGATION IILED AUG. 11, 1909.

Patented Nnv. 17,1914.

5 SHEETS-SHEET UYEHTED STATES PATENT @FFICE.

HENRY EESS, 0F \VAEVA, PENNSYLVANIA, ASSIGNOB. T6 THE HESS-BRIGHT MANU- FACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORFOBATION OF i atenteai Plot. i7, 191%.

Serial No. 512.235.

DELAVIARE.

BIACHINE FOR I'vIEASURING FRICTION.

1,1111%? Specification of Letters Patent.

Application filed August 11, 1909.

To all 71 on: it may cont-om:

lle it known that I. lziirxur lass, a cit-izen of the l'nited States. residing at Wawa, in the county of Delaware and State of Pennsylvania have invented certain new and useful improvements in Machines for Measuring Friction. of which the following a specification. reference being bad therein to the accompanying drawing.

This invention relates UriuettlltilllSiH for measuring; friction between relatively moving parts, and more particularly in bearings ofthe t vpe comprising inner and outer ms in members and intermediate rolling eleuunts and the invention consists of improved mechanism comprising means tor giving support to the parts to be tested, means for moth; one of the parts, and means for subjectuig the other part to load.

More specifically and as applied to bearings compi'. 'ng inner and outer casing members and intermediaterolling elements, the lllQLlitUilSlll embodying my invention comprises means for supporting the bearing to be tested. means for rotating one of the casin; members and means for subjecting the other member of the bearing to load,

acting either radially or cndwise relative to the axis of rotation. or in directions oblique to said axis, the friction between the, parts of the bearing, \Yilhtll under these conditions will tend to rotate the loaded member. being measured and determined by the degree of movementof said loaded member.

l n the accol'npanying drawin :--Figure l is a front elevation of a machine embodying nrv invention and showing the same adapted to subject a bearing to radial loads. Fig.2 is a side elevation of the same with parts in section. Fig. 3 is; afront elevation showing the mechanism adapted to subject a bearing to thrust loads. Fig. l is a side elevation showing the machine adapted to subject the hearings; to both radial and thrust loads. Fig. a horizontal section on the line .u-a2 of Fig. 3. Fig. t3 is a vertical section on the line y-y of Fig. liig. T is a section on the line of Fig. Fig. 8 is a plan view of details.

llcierringr 'e particularly to Figs. 1 and 3. which machine adapted for the determination ol' friction in bearings where the latter are subjected to radial loads the only, 1' represents a bed-plate, from which rises a standard or column *2, supporting at its upper end a system of \vei hing levers, comprising a main horizontal beam 3, fulcrunied between its onus on the standard, and an underlying horizontal lever l, fulcruined at one end on the standard and jointed at its opposite end to the main beam at one side of the fulcrum of the latter by Illtlll-S of a link 5, a weight (5 being adapted to be applied to the opposite end of the same so as to exert an upward pull on the lever livotally connected with the lever -l, preferably by a knife edge, is a depending tension member 7. adapted at its lower end to be engaged with the bearing to be tested. which tension member comprises an upper vertical rod 7- and a lower plate T", jointed together end to end as at T, the rod having its lower end i'orlted for this purpose so as to embrace the upper end of the plate. which latter is formed with an opeir ing' to receive a ltnil'e edge carried between the forlts of the rod.

The barring to he tested is mounted cdly in any suitable manner on the forward end of a horizontal s indle S. mounted for free rotation in the standard and provided with 'i'ast pulley S- adapted to be driven from any suitable source of power, and preferably in opposite-dircetions, for the purpose presently to be described; and in order that hearin of dillerent siz' he applied'to the spindle. the latter is formed at its forward end with a taper bore to receive a taper arbor 9, having on its end a cylindrical stud to it the bore of the inner casing member oi the bearing, the latter being: held thereon by means of a nut 9 which clamps the bearing ring tightly and llllllly against a shoulder .l" on the arbor. number of these arhors may be provided all oi the same diameter to tit the taper bore in the spindle. but havin; atr .s of dillcrentsizes to adapt diil'crent szzed bearings to be applied to the spindle.

in order to adapt the plate 7" to be connected with bearings: oi' dillerent sizes carried by the spindle. a number of disleplatos ll), ll). as shown in are provided of a uniform er-zternal diameter to adapt any of them to he fitted tightly within an opening in the plate 7". the bores of the dilierent disks varying in size to adapt them to it the exterior of the outer casing members of ditlcrent sized hearings to he tested.

In setting the bearing to be tested in place in the machine, the properarbor for the size of the bearing, is fitted in the taper bore of the spindle and the inner casing element of the bearing slipped over the stud, the clamping nut being tightened up so as to hold it firmly and fixedly in position. The appropriate disk is then fitted tightly over the outer casing element, and said disk seated in the pemng in the plate 7 the bore of the latter being so formed that there will be a slight clearance between the plate and disk at the upper side, and the fit of the parts being sulliciently close and tight on the lower side to cause the plate to be moved with the outer casing member as the latter shifts circumferentially when the inner casing member .is rotated. itli the parts assembled in this manner, and the beam 3 properly weighted to subject the outer casing element to the load desired, the weight will tend, through the system: of weighing lovers, to maintain the parts 7* and 7" of the tension member in alinen'ient. 'hen now the spindle carrying the inner casing member is rotated, the friction in the hearing will cause the outer casing member to be shifted circumferentially, which carrying the plate 7* With it, will cause a deflection of the tension member, as indicated to an exaggerated degree by dotted lines in Fig. 1. The journal friction in the bearing being the deflecting force,

is balanced by the weight 6, acting through the weighing beam, and the degree of defiection being determined, the amount of friction may be computed. The degree of deflection may be determined in any suitable manner, but in order to insure accuracy and certainty, I propose to employ a microscope A carried by a bracket a, fixed to the standard 2, the bracket being provided with horizontal guides in which the microscope is mounted so as to be adjustable horizontally by means of a. micrometer screw B, mounted in the bracket and threaded. to the tube of the instrument, The eye-piece of the microscope is provided with cross-hairs adapt ed by the horizontal adjustment of the tube to follow a readin lire on the front face of the rod 7 as the is deflected, and the degree of defie'. is determined by a the microscope and connection with a scale adapted to be r D on the brack In Figs. 3, 4L and 5 .Z-have shown my im proved machine of a form adapted to subject the bearing to end thrust loads and adapted to indicate the friction. Here it will be seen that the bearing to be tested, supported and rotated as in the manner just described, has its outer casing member firmly and tightly engaged by a yoke 15,

to which is connected centrally a torsion member in the 'form of a horizontal Wire 16, fixed at its forward end. to the yoke and passing through openings in the arbor and spindle, with its rear end fixedly connected with the vertical limb 17 of an upright elbow lever 18, fulcrumed in a standard 19, rising from the bed-plate l at the rear end. The other limb of the elbow lever is connected by IllflllS of a vertical connection '20 with a system of weighing levers, comprising a. main horizontal beam 21, fulcrumed' between its ends in the standard, and a horizontal lever 2:2, fulcrumed at one end in the standard and jointed at its opposite end By a connection 23 to the end of the beam, and connected also with the connection 20, before alluded to, a weight 2% being applied to the beam and acting through the parts described to 'pull rearwardly on the torsion wire. As a result of this construction, the outer casing member of the hearing will be subjected to pressure orthrust acting cndwise, that is.

in the direction of the axis of rotation of the bearing. and the circumferential movement of the casing member, due to the friction when the inner member is rotated, will place the wire 10 under torsional strain, which will be resisted by the pull on the wire exerted by the weight through the system of weighing levers, with the result that the friction in the-bearing will be balanced by the torsional re' ance of the torsion member. In this case the degree of movement of the casing member is measured preferably by means of a long pointer 25 fixed to the center of the yoke and adapted to be read in connection with a scale 26 on the standard 2- near its upper end, from which readings-the proper computation may be made to determine the degree of friction relative to the size of the bearing, its lead, etc. In'order to measure the friction. directl y, the yoke has attached to it a delicate balance with weighing pans 27, so that by loading the pan which has been elevated by the movement of the yoke, the amount of weight necessary to restore the balance of the parts measures the degree of friction which caused the deflection. It is important in this mechanism, where the load is applied by a torsion wire or member, that the same be held firmly and fixedly at its ends in the yoke and elbow lever respectively, so that there will be no liability of twisting or slipping relative to said parts. This is conveniently effected by means of taper clamping screws 30 and 31, the former threaded in the yoke, and the latter in a frame 32, carrying a horizontally movable notched block engaging a knife-edge on the vertical limb of the elbow lever. The notched block is'acted on by a screw 33 tapped in the rear end ofthe frame, so that the proper adjustments of the parts may be made to correct any inaccuracies The yoke "is e gaged with the outer casing member of the bearing preferably by notching the ends of its two limbs and applying it by a drivin fit.

it will be of course understood that when the mechanism is employed for measuring friction under thrust loads only, as just described, the tension member and its system of weighing levers, first described, are not employed, it being but necessary in order to render these parts inoperative to remove the disk plate 10 from the plate 7 so that the latter will hang idly and loosely around the bearing being tested for end thrusts.

It is also obvious that when the mechanism is employed for testing radial loads only, first described, the other mechanism for testing end thrustloads is made inoperative.

In order that the friction may he measured when the bearing is subjected to both radial and thrust loads, thereby bringing about a component thrust pressure acting obliquely with relation to the axis of rotation, I propose to employ both in chanisms in combination and simultaneously, a shown in Fig. l, where it will be seen the the outer casing member of the bearing acted on both by the t nsion member I, to apply radial loads, and by the torsion incur her, to apply thrust loads, and the total friction due to the combined load is then measured by determining the deflection of the tension member through the aid of the mic 'iscope, a correction being made for the torsional resistance of the thrust applying Q wire, as this affects slightly the amountof deflection.

I am aware that it has been proposed in the determinatiou'of friction under radial loads; to apply the load to the bearing memher by means of a compression strutf lily invention, where the load is applied by a tension member, possesses advantages over such known constructions, in that the maximum of loads may be applied. without the use of lu-avy or cumbersome parts'which would be necessary in the use olia compression member.

As shown in Fig. l, the rod T of the tension member is in two parts connected by a threaded turnbuckle l, so that when the bearing to be tested is in place and the proper weights hung. the turnbuckle may be adjusted t cll'cct a proper balance ot' all the parts. which balance will be indicated by a pointcc (l on the beam 3 when it lines up with a balan c ma -l-: g on an arm on the upp r end of the standard 2.

in order that any inziccuracy in the initial relative p sitions oi the parts oi the tension member may not incrcasc. or decrease the apparent deflection rcadinfi. the inner casing member of the bearing may be rotated in was? both directions for each test, the arithmetical mean of the two readings giving the correct one.

1 have in the accompanying drawings and.

the "foregoing description illustrated and described the form of mechanism which 1 pre fer to adopt to secure the results desired, and which have been found in practice to answer to an admirable degree the ends to be obtained, but I desire to be understood that the invention is not limited to any specific form or arrangement of the parts except in so far as such limitations are specified in the claims. A

Having thus described my invention, what I claim and desire to secure by Letters ent of the nited States is l. in a machine for measuring "friction between relatively moving parts, the co1nhination of tension member adapted to apply load to one of the parts and capable of being deflected from a neutral position, means for moving the other part, whereby the initial friction between the parts will deflect said tension member from the nentral position, and means for determinately measuring directly the degree oi deflect on oi the said tension member.

2. in a machine for measuring friction between relatively moving parts, the combination of a tension membeadapted to apply load to one of the parts and capable of being deflected from a neutral position, means for moving the other part, whereby the initial -friction between the parts will detlect said tension member, a graduated member, and means for reading directly the degree of deflection of the said tension'memher in connection with said graduated member.

3. In a machine for measuring friction in bearings, t )0 combination of a tension mem-- ber compr sing two sections jointed end to end in line with the longitudinal axes of the said members, and one adapted to be connected with the outer casing member of the bearing, means acting on the otl er section of the tension member and tending to yieldingg'ly extend said sections, and means Pat- , for rotating the inner casing member of the bearing.

'l. in a machine for measuring friction in bearings, the combination oi a plate provided with an opening choir-(din; and adaptcd to be connected with the outer casing: member of the bearing, a rod jointed to the plate winiin the plane of the same, means acting on the rod and tending to extend the plate and rod, and means for rotating the inner casing member.

5. in a machine for measuring friction in bearings. including casing members the combination of means for applying load to one of the (i sing members in the direction of the axis'ol rotation of the bearing, nieai'is for rotating the other casing member of the bearing, and means for measuring the deme of initial frictional deflection of the Toaded casing member.

6, In a machine for testing bearings in-.

eluding casing members, the combination of means for supporting the bearings, a torsion member adapted to be connected with one ofthe easing members of the bearing,

means for subjecting said torsion member to strain, and means for rotating the other casing member of the bearing.-

, 7. In a machine for testing bearings including easing members, the combination of means for supporting the bearing, a yoke adapted to be connected with one of the casing members of the bearing, a torsion member connected with the yoke, means for subjecting the torsion member to strain, and means for rotating the other casing member of the bearing.

S. In a machine for testing hearings including casing members, the combination of means for supporting the bearing, means for applying a pressure component to one of the casing members of the bearing in a diiection oblique to the axis of rotation of said bearing, and means for rotating the other casing member of the bearing.

i). In a machine for testing bearings including casing members, the combination of means for supporting the bearing, means for applying radial pressure to one of the casing-members of thebearing, means for applying end pressure to said casing member, and means for rotating the other casing member of the bearing.

10. In a machine for testing bearings in eluding casing-members, the combination fif .means for supporting the bearing, a tension member adapted to apply a radial load to member will be deflected and the torsion .1-

member twisted, and means for determinately' weighting the loaded casing member in opposition to its deflection to restore the balance.

In testimony whereof I have afiixed my signature in presence of two witnesses.

HENRY HESS. IVitnesses MARY M. CALLA, A. THEO. BRUEGEL. 

